If you insert an image which is too big, the system scales it down to fit into the post. The downside is that you sometimes can't read everything on those downscaled pictures (example).
For an advanced user, that's not a big deal since you right-click the image, copy the image address and open the image in a separate tab.
Normally the system inserts
![enter image description here] for you if you upload an image to imgur.
My feature request is
If the system detects, that the user has chosen an image which will be downscaled (and only then), it could instead insert this syntax:
[![enter image description here]]
The image is now clickable & expandable. You give readers a little bit more comfort.
I don't think that this would be very hard to implement
PS: This is a cool trick, but no one is using it.